Physics of Extraterrestrial Life: Science of UFOs & Search for Intelligent Life - Prof. Ke, Study notes of Physics

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Phys 199ESP

Lecture 3

Are We Alone?

Phys 199ESP

Lecture 3

Extraordinary claims require extraordinary evidence

“Dr. Pitts, I noticed that you will be presenting a lecture entitled ‘The Physics ofUFOs.’ I am not attending the lecture, but would like to know if you have writtenan article on this topic and, if so, whether it is available for

people to read.

On the basis of what I have read, there seems to be a fair amount ofevidence based on (a) reports from highly reliable witnesses (includingformer military people, police officers, and pilots) (b) physical tracefindings, and (c) radar recordings,

which support the hypothesis that at

least some reported UFOs are highly technologically advanced craft thatmay have an extraterrestrial origin.

The ‘Extraterrestrial Hypothesis’

seems plausible for explaining at least some reported UFO sightings. I have also discovered that there is much evidence supporting thehypotheses that our planet Earth is not flat and is not located at the centreof the universe. No testimony is sufficient to establish a miracle, unlessthe testimony be of such a kind that its falsehood wouldbe more miraculous than the fact which it endeavors toestablish…

-David Hume’s maxim

Phys 199ESP

Lecture 3

National Research Council, 2008

“At the present time, given currentknowledge, the level of radiationastronauts would encounter would notallow a human crew to undertake a Marsmission and might also seriously limitlong-term Moon activity.” International Space Station astronautsreceive a radiation dose that is 27 timeshigher than we receive on Earth’s surface. The ISS is still protected by Earth’smagnetic field and upper atmosphere.

Phys 199ESP

Lecture 3

Galaxies

-^ Our sun is a small star toward the outside of the galaxy, theMilky Way (a spiral galaxy) containing^ approximately 200,000,000,000 stars (2 x 10

-^ A few others (e.g. Andromeda)

visible to naked eye

-^ Telescopes

reveal many galaxies, each ~ 10

11 stars

Andromeda

Spiral Galaxy m

Phys 199ESP

Lecture 3

Views from the Hubble Telescope • Picture

of an area of the sky (the sizeof a grain of sandheld at arm’s length)in which there areno stars visible tothe naked eye! • Shows visible starsin the Milky Way anddistant “fuzzy looking” galaxies • Estimate:^11 ~

=100 billion galaxies in the universe

Phys 199ESP

Lecture 3

Material for Life

-^ The earth is teeming with elements:^ – Nitrogen, hydrogen, oxygen, carbon, gold, iron, manganese,uranium, silver, lithium… -^ The big bang (and it’s aftermath) produced noelement heavier than lithium (atomic number=3).^ – Hydrogen, helium and lithium only….nothing heavier.

Atomic # = # of protons H

Phys 199ESP

Lecture 3

Supernova

-^ Expels matter -

all heavy elements in the universe (in

you!) are formed in supernovae • Remnant is a neutron star or black hole • Radiates more energy than an entire galaxy for a briefperiod (months):^ –^ Famous supernovae:^ •

The Christmas Star ??

-^ 1054 --

in Crab Nebula, Recorded in China, …..

-^ 1572 --

in large Magellanic

Cloud, seen by Kepler

-^ Pulsars (Neutron Stars) observed now asremnants of the 1054 and 1572 Supernovae! •^ 1987 --

in Magellanic

Cloud

-^ remnants still

observed

Phys 199ESP

Lecture 3

Summary

-^ About 10

11 stars per galaxy

¾^ 2 to 4 x 10

11 in the Milky Way

-^ About 10

11 galaxies in the universe

-^ So we have about:

11 x 10

100,000,000,000,000,000,000,000 stars in the universe. •^ More stars in the universe than grains of sand on Earth

-^ Universe is dominated by light elements (H, He,Li) but there are plenty of heavy elements thathave been produced by supernovae.

Phys 199ESP

Lecture 3

Does Life Develop?

-^ Experiments show that organic molecules form inconditions similar to the earliest stages of Earth’sdevelopment.^ – Carbon dioxide, water, nitrogen + energy (heat orlighting) -^ Details of the mechanisms that bring singlecelled organisms (like amoeba) from the organicmolecules are under study.^ – Let’s guess that there is only a 1% chance life willdevelop on an Earthlike planet.

[This is probably a low

estimate.

The likelihood to develop life on an Earthlike planet is probably very high.]^8 2 x 10

Earthlike planets x 0.01 chance of developing life = 2 x 10

6 = 2,000,000 planets with life in the Milky Way. [this is still a low estimate]

Phys 199ESP

Lecture 3

Does Intelligence Develop?

-^ Large uncertainty. •^ See Hobson textbook for a discussion.^ –

Art Hobson, “Physics Concepts andConnections”

-^ The Drake Equation attempt to account forthe likelihood of intelligent life to develop,as well as the lifetime “time scale”.^ –

See Origins web site.

Phys 199ESP

Lecture 3

Electromagnetic spectrum^ Electromagnetic spectrum

X‐rays

and

gamma

rays

are

also

light!

Phys 199ESP

Lecture 3

SETI

-^ Search for Extra Terrestrial Intelligence^ – Scanning the sky for all electromagnetic frequencies – Looking for non-random patterns indicating adeterministic source. -^ Note:

Humans have been broadcasting to the

galaxy since the early 20

th^ century.

-^ Our electromagnetic waves now reach out some 80 light-^ years away from us. –^ Anyone farther than 80 light-years would not yet be ableto “see”

our broadcasts!

-^ About 14,000 stars within 100 light-years of us(=0.00000004% of the Milky Way) • For signals originating elsewhere, our sensitivitydepends upon location on time. –^ To “see”

a civilization on the other side of the Milky Way, they needed to begin broadcasting 30,000 years ago!

Phys 199ESP

Lecture 3

-^ Humans have been broadcasting to the galaxysince the early 20

th^ century.

-^ Our electromagnetic waves now reach out some 80 light-^ years away from us. –^ Anyone farther than 80 light-years would not yet be ableto “see”

our broadcasts!

-^ About 14,000 stars within 100 light-years of us(=0.00000004% of the Milky Way) • For signals originating elsewhere, our sensitivitydepends upon location on time. –^ To “see”

a civilization near the center of the Milky Way, How Would They Know We’re Here? they needed to begin broadcasting 25,000 years ago!

Phys 199ESP

Lecture 3 from Atlasoftheuniverse.com

100,000 light years

The Milky Way Galaxy^ Our electromagneticfootprint is smallerthan this dot!^ The rest of the galaxyhas no idea that we arehere!